Leicester City's inability to protect a lead cost them dearly yet again when they conceded a last-minute goal to slip back into the relegation zone.
It had looked as though a Paul Dickov strike midway through the second half would ensure that City celebrated their 4,000th league game with a memorable win against Champions League-chasing Newcastle, but with just seconds remaining Darren Ambrose equalised to silence a record attendance at the Walkers Stadium.
United created the first meaningful chance on four minutes when Nolberto Solano crossed deep for Laurent Robert to hammer an angled volley across the face of Ian Walker's goal.
In the 12th minute Titus Bramble upended Dickov 25 yards out. Muzzy Izzet tapped the ball to Les Ferdinand whose firmly struck shot was blocked by the Newcastle wall.
With Steve Howey having to limp off and be replaced by Matt Elliott, the visitors increased the tempo and only a timely intervention by Matt Elliott at the far post prevented Alan Shearer getting on the end of a Solano free-kick A Muzzy Izzet corner then provoked confusion in the Newcastle defence with Gary Speed almost scoring a spectacular own goal with a diving header, which flew inches wide of an upright.
Five minutes before the break inform Robert hit back for the Magpies with an ambitious 40-yard drive, which Walker was grateful to push over the bar.
United should have taken the lead on 51 minutes with the best chance of the game when Solano and Shearer combined for Lomana LuaLua to slide the ball into Robert's path.
As the Frenchman shaped to shoot, a goal looked certain. But Walker had anticipated the danger to race from his line and block the winger's effort with his feet.
Olivier Bernard and LuaLua both had long-range efforts that were inches away from finding their target as Newcastle began to turn the screw.
City eased the pressure on the hour mark when Izzet's header from a Jordan Stewart cross was on target but Shay Given was well positioned to save.
Then in the 67th minute Leicester grabbed the lead with Dickov scoring his seventh of the season.
A long clearance by the keeper was nodded on by Ferdinand and with Bramble and Aaron Hughes failing to clear, Dickov took full advantage to nip in and crash the ball home from 12 yards.
Bernard was then pole axed when Robert's attempted clearance hit him full on the side of the head, but he was able to continue after lengthy treatment.
Five minutes before the end City almost doubled their lead with Ferdinand heading Izzet's near post corner narrowly wide.
It was a costly miss because Newcastle struck in the last minute when Jermaine Jenas' close-range header was parried by Walker only for substitute Ambrose - who had been on the field for only five minutes - to react quickest to the rebound and nod the loose ball home.